Various hybrid powertrain architectures are known for managing the input and output torques of various prime-movers in hybrid vehicles, most commonly internal combustion engines and electric machines. One such hybrid powertrain architecture comprises a two-mode, compound-split, electro-mechanical transmission which utilizes an input member for receiving power from a prime mover power source and an output member for delivering power from the transmission. First and second motor/generators are operatively connected to an energy storage device for interchanging electrical power between the storage device and the first and second motor/generators. A control unit is provided for regulating the electrical power interchange between the energy storage device and the first and second motor/generators. The control unit also regulates electrical power interchange between the first and second motor/generators.
Engineers implementing powertrain systems including transmission systems are tasked with developing gear shifting schemes. An ongoing challenge with any shifting scheme is to have a gear shift event which may be discernible to an operator, but not displeasing. Furthermore, engineers must be cognizant of thermal energy generated during clutch slippage, and effect of such thermal energy on transmission performance and durability.
Therefore, there is a need to for a method and apparatus to execute a synchronous shift in gears in a hybrid transmission.